Electric hammer and similar tool



A 8 6, 1929- M. D. DOMINGUEZ ELECTRIC HAMMER AND SIMILAR TOQL Filed Jan. 7; 1927 2 Sheets-Sheet ATTORNEYS.

A118? 9- MID. DOMINGUEZ 1,723,607

ELECTRIb HAMMER AND SIMILAR TOOL Filed Jan/'7, 1927 2 Sheets-Sheet a I|||||||||| llli A TTORNEYS.

Patented Aug. 6, 1929.

PATENT OFFICE.

MANUEL D. DOMINGUEZ, OF NEW ORLEANS, LOUISIANA.

ELECTRIC HAMMER AND SIMILAR TOOL.

Application filed January 7, 1927. Serial No. 159,605.

My invention relates to electric hammers v or analogous tools for hammering, riveting,

chipping or similar Operations.

The general object is to provide a tool which is relatively simple, light and compact in proportion to its power, and which can be produced at reasonable cost.

More particular objects are to provide a new and improved arrangement or combination of the frame or casing, a hammer guide tube, a hammer and spring mechanism for'retracting the hammer and yieldingly checking its recoil; to provide a new and improved offset tool or striker which enables the implement to be conveniently used in close places or corners; to provide novel and improved means for circulating air through the interior structure for cooling purposes and especially to provide a novel arrangement or combination of the spring mechanism with suitably arranged air passages for the purpose of providing forced air circulation; to provide an improved readily attachable and detachable auxiliary handle and heat insulating means therefor; to provide various improvements in the hammer proper, as sufiiciently explained hereafter; and to otherwise form and arrange various of the parts in an improved manner for the sake of manufacturing convenience and economy or to improve the operating characteristics of the tool;

The characteristics and advantages of the invention are further sufficiently explained in connection with the following detail description of the accompanying drawing which shows one representative embodiment of the invention. After considering this example, skilled persons will understand that many variations may be made, and I contemplate the employment of any structures that are properly within the scope of the appended claims.

In the drawings:

Fig. 1 is a side elevation of an electric hammer embodying the invention in one form.

Fig. 2 is a vertical section.

Fig. 3 is a top plan of Fig. 4.

Fig. 4 is an elevation of the hammer guide tube with radial pull pieces inserted.

Fig. 5 is a bottom plan of the implement with auxiliary handle parts in section.

Fig. 6 is a diagrammatic View of one sultable controlling or energizing mechanism or circult.

- The casing or frame structure of the tool includes a main or central tubular housing l'which may be of iron or steel, an upper or handle frame 2 which may desirably be of non-ferrous metal, and a bottom plate 3 which may also be non-ferrous. Extending throughout the center of the frame structure is a tubular hammer guide 4 with upper and lower extensions 5 and 6. The tubular main body 1 has upper and lower male conical formations 7 fitting complemental female formations 8 in the lower end of the handle frame and upper face of the bottom plate respectively, and the frame or casing parts are secured together by a nut 9 screwed upon a threaded upper end portion of the guide extension 5 and a tubular screw 10 engaging internal threads in the lower guide extension 6.- This screw has a bottom flange 11 co-operating with an annular face of the bottom plate around its central aperture 12. Desirably, lock washers 13 and 14 are interposed between nut 9 and the upper central face of the hammer frame and between flange 11 and the bottom plate, respectively. By setting up the nut and flange screw sleeve, the conical joint formations of the central housing 1 and the handle frame and bottom plate are brought.

together with a close water and dirt-proof fit and the Washers are also compressed and tight connections are made at these points.

From the main part of the handle frame, arms 15 extend, and the main handle 16 may be made integral with or suitably connected to these arms. One of the arms is cored out to provide a conductor conduit 17 Suitable contact mechanism is enclosed in the handle housing and this mechanism is controlled by a. trigger 18 as usual in tools of this class.

The main or central portion of the guide sleeve has near its upper and lower ends, spaced flanges 19 and 20 formed to provide slots or apertures-for inserted radial laminated core or pole pieces 21. A suitable solenoid 22 is Wound upon the guide sleeve between flanges 20, the outer windings or cover 23 of the solenoid being dimensioned to provide a substantial air space 24 between it and the main casing 1. Circuit connec' lated block 28 on upper guide flange 19 and v from the binding post a conductor 29 goes housing mer body or it may non-ferrous metal,

to one terminal of the solenoid. The other main conductor 30 may be cabled with the conductor 25 and passed into the handle therein, be groundto the frame to which the other solenoid terminal may also be grounded; or a separate conductor (not shown) may go from the second switch terminal to the second solenoid terminal, connection being made by another binding post similar to 27.

The hammer proper, designated as a whole as H, includes a main or body portion 35 having a sliding fit in the main guide sleeve 4. This hammer body is of ferrous metal. Desirably, annularly-spaced grooves or channels 36 are provided in the hammer body near its upper and lower ends, these channels serving to retain oil or grease and thus to aid in properly lubricating the hammer, and also serving to interrupt the surface continuity'of the hammer body and thus tend to reduce eddy current losses. At theupper end of the body is a tubular extension 37 of reduced diameter, the bore of this extension being extended through the hammer body to a point of, for a purpose extension 37 may be later referred to. The tegral with the hambe a separate piece of To control ammer movements in connection with the solenoid action, spring mechanism is provided, as follows: A lower spring washer 40 is located in the lower part of the bore of the guide extension 5 and is dimensioned to have a sliding fit in said bore, and also the washer bore is dimensioned to provide a substantial clearance 41 about the hammer extension. A similar spring washer 42 is located in the upper portion of the guide extension bore and is arranged for similar sliding fit therein, and to have a similar clearance 43 about the hammer extension, these washer clearanc'es being to provide for air circulation and also permit the lubricant oil passlng to the bearing surfaces from oil inlet hole 71, as later explained. The helical spring 44 of suitable compressive force or power is located about the hammer extension with its ends resting in seats formed pn confronting faces of the spring washers. The sprlng is secured and initially compressed to the desired extent by a washer 45 engaged against the upper end of the hammer extension by the nut head of a screw 46. The washer forms the upper hammer abutment and to one terminal of the switch and the other switch terminal may 38 near the lower end thereradial pole pieces and throu for the spring, or more particularly, for the upper spring washer 42, the lower hammer abutment for the lower spring washer 40 consisting of the annular top of the hammer body surrounding the extension. The guide extension 5 is providedv with an internal shoulder 50 forming a lower guide abutment for the spring, or more strictly for the lower spring washer 40, and the upper guide abutment consists of the lower end of a screw plug51 having a nut head 52, the plug screw engaging an internal thread in the upper end of the guide extension and being secured in properly adjusted position by a lock nut 54. The screw plug 51 is properly bored or chambered, as at 55, to provide reciprocating clearance for the screw head 46. A

In addition to its function in securing casing parts together, the tubular fitting or screw sleeve 10 above mentioned, serves as a guide in which the stem 56 of proper, or striker 57, reciprocates. The tool die or other work engaging member may be secured in any convenient way to the striker stem, for example, it may be in line with the stem axis, but an important feature of the invention is the provision of means by which the tool may easily be worked in corners or close places, and for this purpose the striker stem is provided with an oifset portion or arm 58 terminating in a head 59 bored to receive the stem of the tool proper or die 60, which, in this case, is a rivet set. The tool or die stem 61 extends upward through a guide hole in a lug 62 arranged at one side of the bottom plate 3. Undue downward displacement of the striker or displacement of its stem 61 from the guide sleeve is prevented by a stop, such as a cotter pin 63, inserted in the upper end of thedie stem and arranged to engage as best illustrated in Fig. 1, 5

the tool Air circulation, and especially forced circulation for cooling the internal parts, is provided for as follows: Air holes 66 are provided in'the bottom plate admitting air to the chamber 67. Air moving inward or outward may pass therefrom between the h the clearance space 24 around the solenold, between the upper pole pieces tothe chamber 68 above upper guide flange 19 and through the space 69 provided between the upper guide extension 5 and the wall of the handle frame. T0

chamber in the guide extension and the bore communicate with the space 69, air holes 70 or chamber 55 in screw plug 51; and from this access to external atmosphere, is provided by a hole 71 drilled through the center of the screw plug. The air space in the spring chamber also communicates with the bore of hammer extension 37 by means of holes 72 therein. This bore, as previously stated, extends down through the hammer body to the point 38 and at that point intersecting transverse holes 78 are bored, communicating with a clearance space 74 about the lower end of the hammer. This space communicates with a hole 75 bored longitudinally through the striker stem. The clearance 41 between the bore of the lower spring washer and the hammer extension, pre-. vents the formation of a vacuum when the hammer moves downward in relation to the washer, and in this way any vacuum retardation of'hammer movement is avoided. The manner in which air is circulated through, the described passages will be explained in the general functional description.

Desirably, the lower end of the hammer body is formed with an undercut chamber 70 and a disc 77 of non-ferrous metal'is pressed into this chamber in peripheral engagement with the undercut. The upper end of the striker stem is desirably also formed as a shallow extension 78 dimensioned to pass within the shallow hammer chamber and engage the non-magnetic disc 77 therein. This construction or arrangement prevents magnetic adhesion of the hammer to the striker and also obviates objectionable results or effects of peening action on the hammer, or

, striker, or both. The continued operation of the device will naturally cause some peening or metal flow effect upon the hammer, or striker, or both, and. by the described arrangement any such effect with regard. to the hammer is limited to the striking disc 77, and the spread or flow of this disc will be confined to the chamber provided for it in the lower end of the hammer, and similarly the striker top 7 8 of reduced diameter always co-operating with the opening to the disc chamber will have a limited expansion or flow effect, and cannot spread enough to engage the guide sleeve.

To prevent eddy current losses the guide sleeve is desirably split longitudinally as at 80, Fig. 3, and this split or slot may be filled with insulating material 81, such as fibre, wood, micarta etc. and notany metallic material. For asimilar reason the main casing or housing 1 is desirably split, as at 82, Fig. 1 and this split or slot may also be filled with suitable insulating material.

Although these tools may in many cases be operated or held by a single handle, such as the upper handle 16, it is desirable for many purposes and to insure more secure holding and accurate direction of the tool, to provide an additional auxiliary handle,

such as 83, which is desirably made readily attachable and detachable and is also provided with heat insulating means, as follows: The handle proper 83 may be of suitable non-metallic material or of metal and is made hollow to receive the tines 84 of semiannular clamping segments 85 pivotally secured together at 86. Separate insulating segments or a ring 87 of heat insulating material, such as fibre, split at one portion of its periphery as at 88, is placed about the lower part of the casing 1 and the clamping segments 85 are engaged about this insulating ring. The inward end of the handle bore engages beveled formations 89 on the clamping tines 84, The outer ends of these tines are formed as jaws 90 to receive the head of a clamping screw 91 which pro jects through a hole in the outer end of the handle and is there engaged by a clamping nut 92 provided with a spanner hole 93. The handle is slipped over the clamping tines and pressed inward until the screw emerges through the outer end of the handle and then the nut is applied and tightened. This forces the handle inward and by the action of the beveled faces 89 tl1e tines and clamping segments are drawn together tightly, clamping the handle structure upon the hammer casing, and conduction of heat from the hammer structure to the handle is prevented by the insulating material 87, in. an obvious way. The handle may be easily removed and replaced as necessities of use require.

This tool is designed for external control, that is, it is to be energized by an extetnal interrupter, one suitable type of such mechanism beingdiagrammatically illustrated in Fig. 6. This includes an alternator or other suitable source of alternating current, such as power lines, connected to a trans former 101, one terminal of which goes to the hammer solenoid 22. Othertransformer terminals are connected to any suitable rectifier, such as the bulb type rectifier 102 and from this rectifier a lead goes to the hammer switch 103. The operation of such controlling mechanism is well understood in the art.

When the hammer conductors 25 and 30 are properly connected to any suitable external controlling mechanism, such as that described, the trigger 18 is pressed by the operator, the solenoid circuit is closed and the solenoid is intermittently energized by the external-controlling mechanism. At each energization of the solenoid the hammer is pulled smartly downward to'hit'the upper end of the striker stem. In this hammer movement the'lower springwasher 40 remains stationary in engagement with the guide shoulder 50, the upper spring washer moves down in engagement with stop washer 45; the spring is compressed; when the solenoid is deenergized the spring reacts to move the hammer upward and then when the upper spring washer strikes the end of screw plug 51 the spring is again compressed by upward movement of the lower spring washer in contact with the top of the hammer body, and the spring thus yieldingly checks the hammer recoil, and again reacts to urge the hammer downward as the solenoid is again energized. These movements, and especially the movements of the spring washers also facilitate or compel forced circulation of air through the hammer structure for cooling purposes. Thus, whenever through the hammer holes 73 and through the clearance space in the guide sleeve to the bore '75 extending through the striker stem and so to external atmosphere. the recoil stroke of the hammer with accompanying divergent movement of the upper spring washer from the lower one the air flow through both sets of passages will be reversed and similarly it will be understood that upon movements of the lower spring washer toward and from the upper one,

similar air impulses will occur and in this way very effective cooling of the interior structure is provided.

Fig. 1' shows how this hammer with ofiset striker will conveniently work in close places, such as corners of integral or composite I-or-T-beams, or other structural corners or angles.

The upper hammer extension 37 is desirably of non-magnetic material so that this part of the hammer will not be afiected by the magneticflux.

Striker stem 56 may extend more or, less into its guide sleeve. It made longer than shown it will of course be affected more strongly by thepull of the magnet and will,-

in that case, more strongly resist downward movement under impact of the hammer. If the stem is made shorter it is of course farther removed from the magnet field and will oifer less resistance to the hammer.

Of course the. tool is not limited to use p as an electric hammer or riveter, but may be used with chipping tools or in any case where rapid and powerful reciprocation of a striker oranalogous element is desirable.

I claim 1. An implement of the class described comprising a casing, a solenoid therein, a tubular hammer guide extending through the solenoid, a hammer reciprocably located within the guide, a rod extending from the' outer end of the hammer, and spring mechanism located about the hammer extension and including a spring reacting against the hammer and an upper portion of the easing to yieldingly resist down stroke of the hammer, to retract the hammer, to yieldingly check the return stroke and to then assist in propelling the hammer downward whenthe solenoid is reenergized. v

' 2. An implement of the class described comprising a casing, a solenoid therein, a tubular hammer guide extending through the solenoid, a; hammer reciprocably located within the guide, a hammer extension, a spring located about said extension, and upper and lower spring washers cooperating with the spring and abutments on the hammer structure and in the casing respectively to yieldingly resist down stroke of the hammer to retract the hammer, to yieldingly check the return .stroke and to then assist in propelling the hammer downward when-the solenoid is reenergized.

3. An implement of the class described comprising a casing, a, tubular hammer On guide extending therethrough and having an enlarged upper extension, a solenoid located between the guide and the casing, a hammer body arranged for reciprocation in the guide and having an extension extending through the guide extension, spring washers mounted for axial movement about the hammer exten-- sion and controlled by stops on the hammer extension and guide structure, a spring compressed between the spring washers, and a reciprocating striker in the lower end of the casing for cooperation with the hammer.

4. An implement of the class described comprising a casing, a solenoid therein, a tubular hammer guide extending through the solenoid, a tubular hammer reciprocably located within the guide, a tubular hammer extension, and springmechanism cooperating with said extension, the hammer and the hammer guide to yieldingly resist down stroke of the hammer, to retract the hammer, to yieldingly check the return stroke and to then assist in propelling the hammer downward when the solenoid is reenergized, upper and lower portions of the casing structure being provided with air ports and internal parts of the structure being provided with air passages, the spring mechanism and ports being arranged to circulate air through the tubular hammer and extension and otherparts of the interior of the implement.

-5.' An implement of the class described comprising a casing, a solenoid therein, a tubular hammer guide extending through the solenoid, a tubular hammer reciprocably located within theguide, a tubular hammer extension, and spring mechanismincluding reciprocatin washers cooperating with said extension, tie hammer and the hammer guide to yieldingly resist down stroke of the hammer, to retract the hammer, to yieldingly check the return stroke and to then assist in propelling the hammer downward when the solenoid is reenergized, upper and lower portions of the casing structure being provided with air ports and internal parts of the structure being provided with air passages, and the spring washers being arranged to provide forced air circulation through the tubular hammer, hammer extension and other parts of the internal structure by co-operation with said passages and ports.

6. An implement of the class described comprising a casing, a tubular hammer guide extending therethrough and having an enlarged upper extension, a solenoid located between the guide and the casing, a hammer body arranged for reciprocation in the guide ed for axial.movement a out the hammerextension and controlled by stops on the hammer extension and. guide structure, a spring compressed between the spring washers, a reciprocating striker in the lower end of the casing for co-operation with the hammer, the guide extension being arranged as an air chamber in which the reciprocating spring washers act as pistons, said extension having ports communicating with air passages'extending through the casing, and upper and lower portions of the casing being provided with ports, whereby hammer re-. 'ciprocation provides .forced air circulation through the interior structure for cooling purposes.

Signed at New Orleans, in the parish of Orleans and State of Louisiana, this 22nd day of December A. D. 1926.

. MANUEL D. DOMINGUEZ. 

